#define  _CRT_SECURE_NO_WARNINGS 1
#include<iostream>
using namespace std;
void Func(int a = 10, int b = 20, int c = 30) {
	cout << "a=" << a << endl;
	cout << "b=" << b << endl;
	cout << "c=" << c << endl<<endl;
}
int main() {
	Func();
	Func(1);
	Func(1,2);
	Func(1,2,3);
	return 0;
}